A major problem encountered in the production of a two component striped toothpaste is the bleeding of color from one component into the other. This is essentially severe if the colored component is applied to the surface of a white base. In this case the concentration of colorant added to the striping component has to be very high in order to compensate for the thinness of the stripe. If any bleeding is present it is quite noticeable. For this reason a colorant that exhibits no bleeding is required.
Striped dentifrice products containing water soluble dyes are known in the prior art as disclosed in U.S. Pat. No. 4,358,437, U.S. Pat. No. 4,568,534 and U.S. Pat. No. 4,487,757. U.S. Pat. No. 4,358,437 discloses a striped toothpaste wherein the water soluble dye is in a clear gel phase with an opaque paste stripe containing the calcium carbonate abrasive and the metasilicate ingredient within or on the transparent gel containing monofluorophosphate. U.S. Pat. No. 4,568,534 discloses a stripe dentifrice comprising a white anhydrous toothpaste formulation and an aqueous striping composition containing a pH sensitive dye and a gelling agent mixture of carboxymethyl cellulose and calcium carrageenan. U.S. Pat. No. 4,487,757 discloses an effervescent toothpaste extruded from a tube comprising two separate portions, one portion containing sodium bicarbonate particles, stabilized by a compatible water insoluble polishing agent such as calcium carbonate, and a second portion having an acid pH and containing an acid and preferably 0.001 to 0.1% of a coloring agent which is a 1% aqueous dye solution.
However, previous testing has shown that water soluble dyes bleed in our normal stripe formulations. Pigments do not exhibit bleeding. Accordingly, synthetic pigments such as phthalocyanine have been used in a colored dentifrice stripe as disclosed in U.S. Pat. No. 4,456,585 and U.S. Pat. No. 4,518,578. However, said synthetic phthalocyanine pigments are disallowed for use in dentifrices in many countries around the world. Therefore, alternate non-bleeding colorant and/or formulation is needed.
It has been found that naturally occurring organic pigments such as chlorophyllin (green) and B-carbonate (yellow) as colorants showed no bleeding when combined with high levels of xanthan gum (at least 1.6%) in the colored phase of a striped dentifrice.
The prior art also discloses speckled dentifrices wherein the speckles contain a colorant blended with the water-insoluble thermoplastic polymer paricles such as polyethylene, said colorant being a pigment such as ultramarine blue, ferric oxide, metallic lakes and the like, as disclosed in U.S. Pat. No. 3,928,559 and U.S. Pat. No. 4,007,259. U.S. Pat. No. 4,007,259 has addressed the bleeding of colorant from the colored speckle into the toothpaste base by adding 1-5% chloroform to the dental cream, or by adding carnauba wax or a polishing agent to the colored speckles to provide color stability and bleed resistance. U.S. Pat. No. 4,069,311 and U.S. Pat. No. 4,069,312 also disclose speckled dentifrices, wherein said speckles are thermoplastic binder material containing colorants including any physiologically acceptable dye or pigment such as inorganic pigments, organic dyes, metallic lakes thereof, chlorophyll and carotene.
U.S. Pat. No. 3,980,767 discloses a toothpaste consisting of a main transparent gel body free of dental abrasive and containing humectant, thickening agent such as cellulose esters or carrageenates; and a secondary gel body containing a dental abrasive, humectants, thickening agents, detergent and optionally an insoluble coloring material in the form of a contrasting stripe within the main gel body.
However, there is no disclosure in the prior art of a non-bleeding striped dentifrice comprising a white paste dental component and a colored gel dental component having different formulae; said colored component containing the organic pigments beta-carotene or chlorophyllin in a translucent high water gel containing a xanthan gum gelling agent, a sorbitol humectant system and an abrasive polishing agent; said white base component containing the cellulase resistant gelling agent Viscarin (a kappa carrageenan mixture) in an aqueous paste containing glycerin or a mixed humectant system, a polishing agent and other conventional dental ingredients such as anionic surfactant, fluoride-containing compounds, flavors, and the like.